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The Epic Interactive Encyclopedia 1998
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Epic Interactive Encyclopedia, The - 1998 Edition (1998)(Epic Marketing).iso
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Swim_bladder
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INFOTEXT
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1992-09-02
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A thin-walled, air-filled sac found in bony
fishes, between the gut and the spine. Air
enters the bladder from the gut or from
surrounding capillaries, and changes of air
pressure within the bladder maintain buoyancy
whatever the water depth. In evolutionary
terms, the swim bladder of higher fishes is a
derivative of the lungs present in all
primitive fishes (not just lungfishes).